input/Bigram.java
package input;
import java.util.*;
// Can you spot the bug? (Page 188)
public class Bigram {
private final char first;
private final char second;
public Bigram(char first, char second) {
this.first = first;
this.second = second;
」
public boolean equals(Bigram b) (
return b.first == first && b.second == second;
」
public int hashCode(){
return 31 * first + second;
]
public static void main(String[] args)(
Set<Bigram> s = new HashSet<>();
for (int i = 0;i<10；i++)
for (char ch = 'a'; ch <= 'z';ch++)
s.add(new Bigram(ch, ch));
System.out.println(s.size());
